Abstract
Evidence is presented showing that the Cl- uptake process in the squid giant axon is tightly coupled not only to Na+ uptake but also to K+ uptake. Thus, removal of external K+ causes both Cl- and Na+ influxes to be reduced, particularly when [Cl-]i is low, that is, under conditions previously shown to be optimal for Cl-/Na+-coupled influx. In addition, there exists a ouabain-insensitive K+ influx, which depends on the presence of external Cl- and Na+, is inversely proportional to [Cl-]i, and is blocked by furosemide/bumetanide. Finally, this ouabain-insensitive K+ influx appears to require the presence of cellular ATP. The stoichiometry of the coupled transport process was measured using a double-labeling technique combining in the same axon either 36Cl and 42K or 22Na and 42K. The stoichiometry of the flux changes occurring in response either to varying [Cl-]i between 150 and 0 mM or to treatment with 0.3 mM furosemide is, in both cases, approximately 3:2:1 (Cl-/Na+/K+). Although these fluxes require ATP, they are not inhibited by 3 mM vanadate. In addition, treatment with DIDS has no effect on the fluxes.
Full Text
The Full Text of this article is available as a PDF (943.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Aiton J. F., Chipperfield A. R., Lamb J. F., Ogden P., Simmons N. L. Occurrence of passive furosemide-sensitive transmembrane potassium transport in cultured cells. Biochim Biophys Acta. 1981 Sep 7;646(3):389–398. doi: 10.1016/0005-2736(81)90307-2. [DOI] [PubMed] [Google Scholar]
- Boron W. F., Russell J. M. Stoichiometry and ion dependencies of the intracellular-pH-regulating mechanism in squid giant axons. J Gen Physiol. 1983 Mar;81(3):373–399. doi: 10.1085/jgp.81.3.373. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brinley F. J., Jr, Mullins L. J. Sodium extrusion by internally dialyzed squid axons. J Gen Physiol. 1967 Nov;50(10):2303–2331. doi: 10.1085/jgp.50.10.2303. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunham P. B., Stewart G. W., Ellory J. C. Chloride-activated passive potassium transport in human erythrocytes. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1711–1715. doi: 10.1073/pnas.77.3.1711. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ellory J. C., Dunham P. B., Logue P. J., Stewart G. W. Anion-dependent cation transport in erythrocytes. Philos Trans R Soc Lond B Biol Sci. 1982 Dec 1;299(1097):483–495. doi: 10.1098/rstb.1982.0146. [DOI] [PubMed] [Google Scholar]
- Garrahan P. J., Glynn I. M. The sensitivity of the sodium pump to external sodium. J Physiol. 1967 Sep;192(1):175–188. doi: 10.1113/jphysiol.1967.sp008295. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Geck P., Pietrzyk C., Burckhardt B. C., Pfeiffer B., Heinz E. Electrically silent cotransport on Na+, K+ and Cl- in Ehrlich cells. Biochim Biophys Acta. 1980 Aug 4;600(2):432–447. doi: 10.1016/0005-2736(80)90446-0. [DOI] [PubMed] [Google Scholar]
- Greger R., Schlatter E. Presence of luminal K+, a prerequisite for active NaCl transport in the cortical thick ascending limb of Henle's loop of rabbit kidney. Pflugers Arch. 1981 Nov;392(1):92–94. doi: 10.1007/BF00584588. [DOI] [PubMed] [Google Scholar]
- Haas M., Schmidt W. F., 3rd, McManus T. J. Catecholamine-stimulated ion transport in duck red cells. Gradient effects in electrically neutral [Na + K + 2Cl] Co-transport. J Gen Physiol. 1982 Jul;80(1):125–147. doi: 10.1085/jgp.80.1.125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KEYNES R. D. CHLORIDE IN THE SQUID GIANT AXON. J Physiol. 1963 Dec;169:690–705. doi: 10.1113/jphysiol.1963.sp007289. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mullins L. J., Brinley F. J., Jr Potassium fluxes in dialyzed squid axons. J Gen Physiol. 1969 Jun;53(6):704–740. doi: 10.1085/jgp.53.6.704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Musch M. W., Orellana S. A., Kimberg L. S., Field M., Halm D. R., Krasny E. J., Jr, Frizzell R. A. Na+-K+-Cl- co-transport in the intestine of a marine teleost. Nature. 1982 Nov 25;300(5890):351–353. doi: 10.1038/300351a0. [DOI] [PubMed] [Google Scholar]
- Nadarajah A., Leese B., Joplin G. F. Triton X-100 scintillant for counting calcium-45 in biological fluids. Int J Appl Radiat Isot. 1969 Oct;20(10):733–735. doi: 10.1016/0020-708x(69)90071-4. [DOI] [PubMed] [Google Scholar]
- Russell J. M. ATP-Dependent chloride influx into internally dialyzed squid giant axons. J Membr Biol. 1976 Sep 17;28(4):335–349. doi: 10.1007/BF01869704. [DOI] [PubMed] [Google Scholar]
- Russell J. M. Anion transport mechanisms in neurons. Ann N Y Acad Sci. 1980;341:510–523. doi: 10.1111/j.1749-6632.1980.tb47195.x. [DOI] [PubMed] [Google Scholar]
- Russell J. M. Chloride and sodium influx: a coupled uptake mechanism in the squid giant axon. J Gen Physiol. 1979 Jun;73(6):801–818. doi: 10.1085/jgp.73.6.801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schmidt W. F., 3rd, McManus T. J. Ouabain-insensitive salt and water movements in duck red cells. III. The role of chloride in the volume response. J Gen Physiol. 1977 Jul;70(1):99–121. doi: 10.1085/jgp.70.1.99. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Warnock D. G., Eveloff J. NaCl entry mechanisms in the luminal membrane of the renal tubule. Am J Physiol. 1982 Jun;242(6):F561–F574. doi: 10.1152/ajprenal.1982.242.6.F561. [DOI] [PubMed] [Google Scholar]